The invention relates to a composition for dyeing keratin fibres, and in particular human keratin fibres such as the hair, comprising, in a medium which is suitable for dyeing, at least one cationic direct dye and at least one auto-oxidizable dye, as well as to the dyeing process using this composition.
It is known practice to dye keratin fibres, and in particular human hair, with dye compositions containing auto-oxidizable dyes such as benzene derivatives containing at least three hydroxyl and/or amino groups and indole derivatives, such as 5,6-dihydroxyindole. These auto-oxidizable dyes have the particular feature of being able to be oxidized without any oxidizing agent other than atmospheric oxygen, to give rise to coloured and colouring molecules. However, the colorations obtained using these dyes are still not satisfactory, in particular as regards their intensity and their chromaticity.
It is also known practice to dye keratin fibres with direct dyes, and in particular with cationic direct dyes. Direct dyes have the drawback, when they are incorporated into dye compositions, of leading to colorations which are of insufficient staying power, in particular with respect to shampooing.
The Applicant has now discovered that it is possible to obtain novel compositions for dyeing keratin fibres, which are capable of leading to intense, unselective colorations which show good resistance to the various attacking factors to which the hair may be subjected, by combining at least one cationic direct dye and at least one auto-oxidizable dye.
This discovery forms the basis of the present invention.
A first subject of the invention is thus a ready-to-use composition for dyeing keratin fibres, and in particular human keratin fibres such as the hair, characterized in that it comprises, in a medium which is suitable for dyeing:
at least one cationic direct dye,
at least one auto-oxidizable dye.
The ready-to-use dye composition in accordance with the invention leads to intense, chromatic colorations which show low selectivity and excellent properties of resistance both with respect to atmospheric agents such as light and bad weather, and with respect to perspiration and the various treatments to which the hair may be subjected (washing, permanent-waving).
A subject of the invention is also a process for dyeing keratin fibres using this ready-to-use dye composition.
The cationic direct dye(s) which can be used in the ready-to-use dye composition in accordance with the invention is (are) preferably chosen from cationic aminoanthraquinone dyes, cationic monoazo or diazo dyes and cationic naphthoquinone dyes.
By way of example, mention may be made in particular of [8-[(p-aminophenyl)azo]-7-hydroxy-2-naphthyl]trimethylammonium chloride (also known as Basic Brown 16 or Arianor Mahogany 306002 in the Color Index), 3-[(4-amino-6-bromo-5,8-dihydro-1-hydroxy-8-imino-5-oxo-2-naphthalenyl)amino]-N,N,N-trimethyl-benzenaminium chloride (also known as Basic Blue 99 or Arianor Steel Blue 306004 in the Color Index), 7-hydroxy-8-[(2-methoxyphenyl)azo]-N,N,N-trimethyl-2-naphthalenaminium chloride (also known as Basic Red 76 or Arianor Madder Red in the Color Index), [8-[(4-amino-2-nitrophenyl)azo]-7-hydroxy-2-naphthyl]-trimethylammonium chloride (also known as Basic Brown 17 or Arianor Sienna Brown 306001 in the Color Index) and 3-[(4,5-dihydro-3-methyl-5-oxo-1-phenyl-1H-pyrazol-4-yl)azo]-N,N,N-trimethylbenzenaminium chloride (also known as Basic Yellow 57 or Arianor Straw Yellow 306005 in the Color Index).
The cationic direct dye(s) can also be chosen from:
a) the compounds of formula (I) below: 
xe2x80x83in which:
D represents a nitrogen atom or a xe2x80x94CH group,
R1 and R2, which may be identical or different, represent a hydrogen atom; a C1-C4 alkyl radical which can be substituted with a xe2x80x94CN, xe2x80x94OH or xe2x80x94NH2 radical; or form, with a carbon atom of the benzene ring, an optionally oxygenated or nitrogenous heterocycle, which can be substituted with one or more C1-C4 alkyl radicals; a 4xe2x80x2-aminophenyl radical,
R3 and Rxe2x80x23, which may be identical or different, represent a hydrogen or halogen atom chosen from chlorine, bromine, iodine and fluorine, or a cyano, C1-C4 alkoxy or acetyloxy radical,
Xxe2x88x92 represents an anion preferably chosen from chloride, methyl sulphate and acetate,
A represents a group chosen by structures A1 to A19 below: 
in which R4 represents a C1-C4 alkyl radical which can be substituted with a hydroxyl radical and R5 represents a C1-C4 alkoxy radical, with the proviso that when D represents xe2x80x94CH, when A represents A4 or A13 and when R3 is other than an alkoxy radical, then R1 and R2 do not simultaneously denote a hydrogen atom;
b) the compounds of formula (II) below: 
xe2x80x83in which:
R6 represents a hydrogen atom or a C1-C4 alkyl radical,
R7 represents a hydrogen atom, an alkyl radical which can be substituted with a xe2x80x94CN radical or with an amino group, a 4xe2x80x2-aminophenyl radical or forms, with R6, an optionally oxygenated and/or nitrogenous heterocycle which can be substituted with a C1-C4 alkyl radical,
R8 and R9, which may be identical or different, represent a hydrogen atom, a halogen atom such as bromine, chlorine, iodine or fluorine, a C1-C4 alkyl or C1-C4 alkoxy radical or a xe2x80x94CN radical,
Xxe2x88x92 represents an anion preferably chosen from chloride, methyl sulphate and acetate,
B represents a group chosen by structures B1 to B6 below: 
in which R10 represents a C1-C4 alkyl radical, R11, and R12, which may be identical or different, represent a hydrogen atom or a C1-C4 alkyl radical;
c) the compounds of formulae (III) and (IIIxe2x80x2) below: 
xe2x80x83in which:
R13 represents a hydrogen atom, a C1-C4 alkoxy radical, a halogen atom such as bromine, chlorine, iodine or fluorine, or an amino radical,
R14 represents a hydrogen atom, a C1-C4 alkyl radical or forms, with a carbon atom of the benzene ring, a heterocycle which is optionally oxygenated and/or substituted with one or more C1-C4 alkyl groups,
R15 represents a hydrogen atom or a halogen atom such as bromine, chlorine, iodine or fluorine,
R16 and R17, which may be identical or different, represent a hydrogen atom or a C1-C4 alkyl radical,
D1 and D2, which may be identical or different, represent a nitrogen atom or a xe2x80x94CH group,
m=0 or 1,
it being understood that when R13 represents an unsubstituted amino group, then D1 and D2 simultaneously represent a xe2x80x94CH group and m=0,
Xxe2x88x92 represents an anion preferably chosen from chloride, methyl sulphate and acetate,
E represents a group chosen by structures E1 to E8 below: 
in which Rxe2x80x2 represents a C1-C4 alkyl radical;
when m=0 and when D1 represents a nitrogen atom, then E can also denote a group of structure E9 below: 
in which Rxe2x80x2 represents a C1-C4 alkyl radical.
The cationic direct dyes of formulae (I), (II), (III) and (IIIxe2x80x2) which can be used in the ready-to-use dye compositions in accordance with the invention are known compounds and are described, for example, in patent applications WO 95/01772, WO 95/15144 and EP-A-0,714,954.
Among the cationic direct dyes of formula (I) which can be used in the ready-to-use dye compositions in accordance with the invention, mention may be made more particularly of the compounds corresponding to structures (I1) to (I52) below: 
Among the compounds of structures (I1) to (I52) described above, the compounds most particularly preferred are the ones corresponding to structures (I1), (I2), (I14) and (I31).
Among the cationic direct dyes of formula (II) which can be used in the ready-to-use dye compositions in accordance with the invention, mention may be made more particularly of the compounds corresponding to structures (II1) to (II12) below: 
Among the cationic direct dyes of formula (III) which can be used in the ready-to-use dye compositions in accordance with the invention, mention may be made more particularly of the compounds corresponding to structures (III1) to (III18) below: 
Among the specific compounds of structures (III1) to (III18) described above, the compounds most particularly preferred are the ones corresponding to structures (III4), (III5) and (III13).
Among the cationic direct dyes of formula (IIIxe2x80x2) which can be used in the ready-to-use dye compositions in accordance with the invention, mention may be made more particularly of the compounds corresponding to structures (IIIxe2x80x21) to (IIIxe2x80x23) below: 
The cationic direct dye(s) used according to the invention preferably represent(s) from 0.001 to 10% by weight approximately relative to the total weight of the ready-to-use dye composition, and even more preferably from 0.05 to 5% by weight approximately relative to this weight.
The nature of the auto-oxidizable dye(s) used in the ready-to-use dye composition is not critical. It (they) can be chosen in particular from benzene, indole or indoline auto-oxidizable dyes.
Among the benzene auto-oxidizable dyes which can be used in the dye composition in accordance with the invention, mention may be made more particularly of the compounds of formula (IV) below, and the addition salts thereof with an acid: 
in which:
R18 represents a hydrogen atom, a C1-C4 alkyl radical or an amino radical,
R19 represents a C1-C4 alkyl, hydroxyl, amino, mono(C1-C4)alkylamino or di(C1-C4)alkylamino radical,
R20 represents a hydrogen atom or a hydroxyl or amino radical,
R21 represents a hydrogen atom or an amino radical;
it being understood that at least two of the radicals R19 to R21 represent, independently of each other, a hydroxyl, amino, mono(C1-C4)alkylamino or di(C1-C4)alkylamino radical.
Among the benzene auto-oxidizable dyes of formula (IV) above, mention may be made more particularly of 1,2,4-trihydroxybenzene, 1-methyl-2,4,5-trihydroxybenzene, 2,4-diamino-6-methylphenol, 2-amino-4-methylaminophenol, 2,5-diamino-4-methyl-phenol, 2,6-diamino-4-diethylaminophenol and 2,6-diamino-1,4-dihydroxybenzene, and the addition salts thereof with an acid.
Among the indole and indoline auto-oxidizable dyes which can be used in the dye composition in accordance with the invention, mention may be made in particular of the compounds of formulae (V) and (VI) below: 
in which:
R22, R24, R25, and R26, which may be identical or different, represent a hydrogen atom or a C1-C4 alkyl or C1-C4 acyl radical,
R23 represents a hydrogen atom, a C1-C4 alkyl radical or a carboxyl radical.
Among the auto-oxidizable dyes of formula (V) above, mention may be made more particularly of 5,6-dihydroxyindole, 2-methyl-5,6-dihydroxyindole, 3-methyl-5,6-dihydroxyindole, 1-methyl-5,6-dihydroxy-indole, 2,3-dimethyl-5,6-dihydroxyindole, 5-methoxy-6-hydroxyindole, 5-acetoxy-6-hydroxyindole, 5,6-diacetoxyindole and 5,6-dihydroxy-2-indole-carboxylic acid, and the addition salts thereof with an acid.
Among the auto-oxidizable dyes of formula (VI) above, mention may be made more particularly of 5,6-dihydroxyindoline, 1-methyl-5,6-dihydroxyindoline and 1-ethyl-5,6-dihydroxy-indoline, and the addition salts thereof with an acid.
The auto-oxidizable dye(s) preferably represent(s) from 0.0005 to 12% by weight approximately relative to the total weight of the dye composition in accordance with the invention, and even more preferably from 0.005 to 8% by weight approximately relative to this weight.
In order to facilitate the oxidation of the auto-oxidizable dyes, the ready-to-use dye composition in accordance with the invention can also contain one or more oxidizing agents. These oxidizing agents can be chosen in particular from hydrogen peroxide, urea peroxide, alkali metal bromates, persalts such as perborates and persulphates, and enzymes such as peroxidases and two-electron oxidoreductases.
Among the 2-electron oxidoreductases which can be used as oxidizing agents in the ready-to-use dye composition in accordance with the invention, mention may be made more particularly of pyranose oxidases, glucose oxidases, glycerol oxidases, lactate oxidases, pyruvate oxidases and uricases.
According to the invention, the use of uricases of animal, microbiological or biotechnological origin is particularly preferred.
By way of example, mention may be made in particular of the uricase extracted from boar liver, the uricase from Arthrobacter globiformis and the uricase from Aspergillus flavus. 
The 2-electron oxidoreductase(s) can be used in pure crystalline form or in a form diluted in a diluent which is inert with respect to the said 2-electron oxidoreductase.
When they are used, the 2-electron oxidoreductase(s) in accordance with the invention preferably represent(s) from 0.01 to 200 by weight approximately relative to the total weight of the ready-to-use dye composition, and even more preferably from 0.1 to 50 by weight approximately relative to this weight.
When an enzyme of 2-electron oxidoreductase type is used in accordance with the invention, the ready-to-use dye composition can also contain one or more donors.
According to the invention, the term xe2x80x9cdonorxe2x80x9d refers to the various substrates involved in the functioning of the said 2-electron oxidoreductase(s).
The nature of the donor (or substrate) used varies as a function of the nature of the 2-electron oxidoreductase which is used. For example, D-glucose, L-sorbose and D-xylose may be mentioned as donors for pyranose oxidases; D-glucose may be mentioned as a donor for glucose oxidases; glycerol and dihydroxyacetone may be mentioned as donors for glycerol oxidases; lactic acid and its salts may be mentioned as donors for lactate oxidases; pyruvic acid and its salts may be mentioned as donors for pyruvate oxidases; and lastly, uric acid and its salts may be mentioned as donors for uricases.
When they are used, the donor(s) (or substrate(s)) used in accordance with the invention preferably represent(s) from 0.01 to 20% by weight approximately relative to the total weight of the ready-to-use dye composition in accordance with the invention, and even more preferably from 0.1 to 5% approximately relative to this weight.
When the ready-to-use dye composition in accordance with the invention contains an oxidizing agent, it can also contain one or more oxidation bases and/or one or more couplers. These oxidation bases can be chosen in particular from para-phenylenediamines, para-aminophenols, ortho-phenylenediamines and heterocyclic bases such as, for example, pyridine derivatives, pyrimidine derivatives, pyrazole derivatives and pyrazolopyrimidine derivatives. The couplers can be chosen in particular from meta-phenylenediamines, meta-aminophenols, meta-diphenols, heterocyclic couplers such as, for example, indole derivatives, indoline derivatives, benzimidazole derivatives, benzomorpholine derivatives, sesamol derivatives, pyridine, pyrimidine and pyrazole derivatives, and the addition salts thereof with an acid.
When they are present, the oxidation base(s) preferably represent(s) from 0.0005 to 12% by weight approximately relative to the total weight of the dye composition in accordance with the invention, and even more preferably from 0.005 to 8% by weight approximately relative to this weight.
When they are present, the coupler(s) preferably represent(s) from 0.0001 to 10% by weight approximately relative to the total weight of the ready-to-use dye composition, and even more preferably from 0.005 to 80 by weight approximately relative to this weight.
In general, the addition salts with an acid which can be used in the context of the dye compositions of the invention (auto-oxidizable dyes, oxidation bases and couplers) are chosen in particular from the hydrochlorides, hydrobromides, sulphates, tartrates, lactates and acetates.
The medium which is suitable for dyeing (or support) for the ready-to-use dye composition in accordance with the invention generally consists of water or of a mixture of water and at least one organic solvent to dissolve the compounds which would not be sufficiently water-soluble. As organic solvents, mention may be made, for example, of C1-C4 alkanols, such as ethanol and isopropanol, as well as aromatic alcohols such as benzyl alcohol or phenoxyethanol, similar products and mixtures thereof.
The pH of the ready-to-use composition in accordance with the invention is generally between 5 and 11 approximately and preferably between 6.5 and 10 approximately. It can be adjusted to the desired value by means of acidifying or basifying aids usually used for dyeing keratin fibres.
Among the acidifying agents, mention may be made, by way of example, of inorganic or organic acids such as hydrochloric acid, orthophosphoric acid, sulphuric acid, carboxylic acids such as acetic acid, tartaric acid, citric acid and lactic acid, and sulphonic acids.
Among the basifying agents, mention may be made, by way of example, of aqueous ammonia, alkaline carbonates, alkanolamines such as mono-, di- and triethanolamine, 2-methyl-2-amino-1-propanol and derivatives thereof, sodium hydroxide, potassium hydroxide and the compounds of formula (VII) below: 
in which W is a propylene residue optionally substituted with a hydroxyl group or a C1-C4 alkyl radical; R27, R28, R29 and R30, which may be identical or different, represent a hydrogen atom or a C1-C4 alkyl or C1-C4 hydroxyalkyl radical.
The ready-to-use dye composition in accordance with the invention can also contain various adjuvants conventionally used in compositions for dyeing the hair, such as, for example, antioxidants, penetrating agents, sequestering agents, fragrances, buffers, dispersing agents, preserving agents and opacifiers.
Needless to say, a person skilled in the art will take care to select this or these optional complementary compounds such that the advantageous properties intrinsically associated with the ready-to-use dye composition in accordance with the invention are not, or are not substantially, adversely affected by the addition(s) envisaged.
The ready-to-use dye composition in accordance with the invention can be in various forms, such as in the form of liquids, creams or gels, which may be pressurized, or in any other form which is suitable for dyeing keratin fibres, and in particular human hair. It must be free of gaseous oxygen, so as to avoid any premature oxidation of the auto-oxidizable dye(s).
A subject of the invention is also a process for dyeing keratin fibres, and in particular human keratin fibres such as the hair, using the ready-to-use dye composition as defined above.
According to this process, at least one ready-to-use dye composition as defined above is applied to the fibres, for a period which is sufficient to develop the desired coloration, after which the fibres are rinsed, optionally washed with shampoo, rinsed again and dried.
The time required to develop the coloration on the keratin fibres is generally between 3 and 60 minutes and even more precisely between 5 and 40 minutes.
According to one specific embodiment of the invention and when the ready-to-use composition in accordance with the invention contains an oxidizing agent, the process includes a preliminary step which consists in separately storing, on the one hand, a composition (A) comprising, in a medium which is suitable for dyeing, at least one cationic direct dye, and at least one auto-oxidizable dye, and, on the other hand, a composition (B) containing, in a medium which is suitable for dyeing, at least one oxidizing agent, and then in mixing them together at the time of use, before applying this mixture to the keratin fibres.
Another subject of the invention is a multi-compartment dyeing device or xe2x80x9ckitxe2x80x9d or any other multi-compartment packaging system, a first compartment of which contains composition (A) as defined above and a second compartment of which contains composition (B) as defined above. These devices can be equipped with a means for applying the desired mixture to the hair, such as the devices described in patent FR-2,586,913 in the name of the Applicant.
The examples which follow are intended to illustrate the invention without, however, limiting its scope.